Analog Signal - A signal in which pixel information is relayed via waves of fluctuating voltage. This is the standard means of transmitting data to a monitor.

Aperture Grille - A set of vertical metal bars that directs the electron beam in a CRT so that it strikes only the phosphors of a desired color.

Aspect Ratio - A comparison between the relative width and height of a computer screen. For example, the standard 4:3 aspect ratio is 4 units wide and 3 units high. The other major aspect ratio found in computer monitors is the 16:9 HDTV standard.

Cathode-Ray Tube (CRT) - The vacuum tube used in most standard monitors and televisions. Inside the tube, an electron beam passes back and forth, illuminating phosphors on the screen. These phosphors make up the image we see.

CCFL (Cold Cathode Fluorescent Lamp) - A type of backlight used in many LCDs.

CD/M2 - The basic measurement of a monitor's brightness. 1 cd/m2 is equal to the amount of light a single wax candle would give off over one square meter.

CFL (Cold Fluorescent Light) - See CCFL

Component - A video connection scheme that separates the Red, Green, and Blue signals and transmits them across separate cables. The actual connectors on the cables can be either RCA or BNC.

Composite - A video connection method that combine the Red, Green, and Blue signals and carries them on one cable. These usually feature RCA connectors.

Contrast Ratio - The contrast ratio is the comparison between the darkest black and the brightest white that can be shown onscreen. The higher the contrast ratio, the more clear definition there is between light and dark.

Frequency - The measurement of the amount of waves transmitted in an analog signal over a one-second period, usually expressed in Hertz. The higher the frequency, the faster a monitor's screen is redrawn and the smoother motion appear.

I/O Port (Input/Output Port) - A bi-directional port that allows data to be transmitted back and forth between devices.

Interface - A means of communicating between two different devices.

Interlaced - An interlaced image is created when the cathode ray fills in even-numbered horizontal lines on one pass, and then odd-numbered lines on the second pass. This process, found mainly in older monitors, can create some onscreen flicker.

LED (Light Emitting Diode) - A type of backlight used in some flat-screen monitors. LEDs warm up and emit light when they are electrically charged. These are generally not as bright as a CCFL.

Light Source - The type of lamp used in an LCD monitor.

Liquid Crystal Display (LCD) - A monitor that uses fluorescent backlights, color filters, and groups of liquid crystals to form the onscreen image. When an electrical signal is sent to the screen, the crystals react by either filtering out or projecting light onscreen.

Non-interlaced - A non-interlaced image is created when the cathode ray fills-in all horizontal lines in one pass. This creates a flicker-free onscreen image. All modern CRT monitors feature non-interlaced displays.

Passive Matrix - Passive matrix displays use wire grids to indirectly activate an LCD screen's diodes. Because of the indirect current, the images aren't quite as bright as other technologies.

Phosphor - A chemical compound that emits light when excited by electrons. Different formulations produce lights of different colors.

Pixel (Picture Element) - The small cells that visually combine to form images on a screen. Each individual pixel on a monitor is made up of three separate colors (Red, Green, and Blue).

Pixel Pitch - The distance between the center of a phosphor dot of a given color and the center of the next nearest dot of the same color.

Plasma Display - A monitor that uses neon and xenon gas sealed between plates to make up the screen image. Electrodes excite the gasses, causing them to change into UV emitting plasma, which then charges phosphors and creates what the viewer sees. These displays feature thin profiles, large screens, and incredibly vibrant images.

Plug-and-Play (PnP) - A configuration standard that allows a newly installed device to set itself up in the operating system automatically.

Port - The interface in which you connect components to a computer system.

RAM (Random Access Memory) - A temporary data storage found in computers and some of their components. It acts as a holding area for data that is waiting to be used.

RCA Connection - A standard connection type found on most video-based consumer electronics.

Resolution - The amount of pixels displayed onscreen vertically times the amount displayed horizontally. The higher the resolution, the more information that can be displayed onscreen. There are a number of standard resolutions, which include: